Question: $ { \left[\begin{array}{rr}{-1} & {3} \\ {-1} & {1}\end{array}\right]-\left[\begin{array}{rr}{1} & {4} \\ {1} & {4}\end{array}\right] = {?} } $
Solution: To find the difference of two matrices, subtract the corresponding items between each matrix. ${\left[\begin{array}{rr}{-1}-{1} & {3}-{4} \\ {-1}-{1} & {1}-{4}\end{array}\right]}$ Now, simplify: ${\left[\begin{array}{rr}{-2} & {-1} \\ {-2} & {-3}\end{array}\right]}$